Utility of horizontal and vertical sections of scalp biopsies in various forms of primary alopecias

BACKGROUND: This study was performed to demonstrate the usefulness of horizontal and vertical sections of scalp biopsies in diagnosing various forms of primary alopecias and to highlight the importance of error-free grossing. MATERIALS AND METHODS: A retrospective analytical review of 228 scalp biopsies was done, noting down the diagnostic histopathological features evident in horizontal and vertical sections of each cases. The idealness of the sections, especially horizontal section, was also analyzed. RESULTS: Out of the 228 cases, 44 scalp biopsies were classified histologically as cicatricial alopecias and the remaining 162 as noncicatricial alopecia. 22 cases were inconclusive owing to erroneous grossing. We found horizontal sections to be more useful in cases of noncicatricial alopecias, whereas vertical sections proved superior in cicatricial alopecias. CONCLUSION: Combining both horizontally and vertically sectioned scalp biopsies maximizes the diagnostic yield. When a single biopsy is submitted, the choice between horizontal and vertical section should depend on clinical diagnosis/suspicion.